Stone disc grinding mills, with unitary material impeller secured to runner stone



March l5, 1955 M. MACEK, SR 2,704,139

STONE DISC GRINDING MILLS, WITH UNITARY MATERIAL IMPELLER SECURED TO UNNER STONE Filed June 12, 52

' IN VEN TOR. M477 M/lCL-K, 5/9.

ATTORNEY United States Patent STONE DISC GRINDING MILLS, WITH UNITARY lgII%TNI%RIAL IMPELLER SECURED T0 RUNNER Matt Macek, Sr., Cedar Rapids, Iowa, assignor to Matt Macek, (in, Cedar Rapids, Iowa Application June 12, 1952, Serial No. 293,139

3 Claims. (Cl. 241-245) This invention relates to grinding mills and particularly to improvements in such devices, such as will facilitate service and maintenance operations and increase the grmdmg efiiciency in such mills.

Grinding mills of the type with which this invention is concerned, usually employ a circular, hollow center runner or rotatable mill stone disposed above and rotatable on a circular bed or lower mill stone, the annular faces of the milling stones in contact with one another being notched or grooved so as to increase the milling elnciency and the milling capacity of the stones.

Grinding mills of this type are, of necessity, quite large and cumbersome and very heavy. In normal operation, the grinding slots or cracks wear quite rapidly and, further, as a natural result of the stones rotating in one direction only, one edge of each grinding crack only is effective in grinding. It has, therefore, been necessary in the past to dismantle such mills quite frequently, often every few days in order to redress the milling surfaces of the stones.

This is naturally a slow and expensive operation, and particularly expensive in view of the enforced shut-down of the mill which, in normal usage, may have a capacity of hundreds of bushels of grain a day.

It is therefore a primary object of my invention to provide improvements in such grinding mills as will reduce the frequency at which the milling stones need redressing, and thus ultimately result in an increase in the life of the mill stones themselves.

Still another object of myinvention is the provision of improved means for pumping or forcing the material to be ground outwardly between the milling faces of the stones.

Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawings and following specifications, wherein are disclosed several exemplary embodiments of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claims, without departing from the spirit of the invention.

In said drawings:

Figure 1 is a view generally in vertical section taken through a grinding mill constructed in accordance with my invention.

Figure 2 is a plan view of the under side of the runner stone, and as taken generally along the lines 2-2 of Figure 1, and

Figure 3 is a view in perspective of a removable pump or feeder vane holder.

Referring now to the drawings, and particularly to Figures 1 and 2 thereof, in which is illustrated amill having a bed stone, indicated generally at 10, and a runner stone indicated generally at 11, the latter being driven by and pivotally supported upon a vertically adjustable drive shaft 12. A bed stone, as usually constructed, consists of a hollow-center cylinder of stone or other abrasive material 13, mounted in a steel ring or shell 14 on a cylindrical slab 16 of concrete or the like. The drive shaft 12 passes upwardly through an axially positioned gland or bearing 17.

The runner stone 11 is similarly constructed, with a hollow-center, cylindrically-shaped milling stone 18 set into a circular cap stone 19 of concrete or the like, both being encircled by means of a steel band 21. Material to be milled is fed downwardly from the hopper 22 through the hollow center of the runner stone, the material passing through an axially aligned opening 23 in the cap stone within which the driving dog or spider 24 is engaged.

Various devices have been employed for pumping or feeding material outwardly between the milling surfaces of the grinding stones. One of said methods is illustrated in Patent No. 2,330,067 issued September 1, 1943, to Matt Macek, Sr., et al. It is a purpose of the present invention to provide a material pumping assembly or impeller which may be readily and quickly removed as a unit, so as to eliminate interference with the tools used in redressing the stones when redressing becomes neceslsazlrrg and, further, to permit ready reversal of the impeller a es.

This impeller assembly, which I have indicated generally at 26, is best illustrated in Figure 3, and comprises a plurality of open ended, generally rectangular sleeves or paddle holders 27 radially spaced about an annular mounting plate 28. These impeller holders may be welded to the annular mounting plate 28 and encircled by a reinforcing ring 29. Several holes 31 may be provided in the circular plate 28 for the reception of bolts 32, best shown in Figure 2 and by means of which the entire impeller assembly is secured within the hollow center well 30 of the runner stone.

The concrete cap 19 is provided with an annular recess to receive the edge of the ring 29, and is also. provided with triangular shaped recesses 33, best shown in Figure 2, for the reception of the impeller boxes 27. It will be noted that the impeller boxes 27 extend equal distances on opposite sides of the circular plate 28, and by turning this plate upside down, the impellers, indicated at 34 and preferably constructed of wood or the like, may be caused to feed material outwardly to the stones when the direction of rotation of the runner stone isreversed.

The impeller blades themselves may be adjusted vertically in the sleeves 27 and secured in position by means of bolts or the like, as indicated at 36.

The impeller assembly 26 has been partially broken away in Figure 2 so as to better show the structure thereof and the relationship of the impellers with the stone and with the recesses therein.

In normal use, one side of each groove takesthe wear, and so long as the groove remains deep enough, the other side of the groove is, for all practical purposes, self sharpening. Therefore by reversing the direction of rotation of the runner stone, it is possible to utilize this inherent characteristic of mill stones. The applicants improved impeller structure permits the paddles 34 to be reversed. To accomplish this, the runner stone must of course be lifted and the four anchor bolts 32 removed. The impeller plate 28 may now be removed and the wooden paddles 34 moved so as to extend from the opposite ends of the sleeves 27. The impeller assembly may now be replaced within the runner stone but in inverted position. Thus the pumping device will function properly to feed material outwardly between the milling stones when the rotation of the runner stone is reversed.

Although I have shown and described a specific embodiment of my invention, it is apparent that modifications thereof may be made by those skilled in the art. Such modifications may be made without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim as my invention:

1. In a grinding milling mill of the disc type having a stationary bed stone and a rotatable runner stone mounted in a cap stone for rotation thereabove and each of said stones having generally cylindrical cavities in their adjoining faces and spaced from their outer edges, a unitary impeller mounting member comprising a generally circular plate, a plurality of equally circnmferentially spaced paddle holders attached thereto and extending generally at right angles to said circular plate, impeller blades detachably attached to said holders, means for detachably securing the unitary impeller to the runner stone within its cavity, and triangular-shaped recesses positioned within said cap stone to receive said holders and impeller blades.

2. In a grinding mill of the disc type having a stationary mill stone and a rotatable mill stone having a cap stone, the said mill stones being provided with cavities in their adjoining faces, a unitary impeller comprising a generally circular plate having a reinforcing ring on the outer edge thereof, said impeller being receivable within the cavity of the runner stone and detachably attached to the cap stone, a plurality of paddle sleeves equally circumferentially spaced about the said circular plate and extending generally at right angles to the surface thereof, paddle members detachably secured in and extending outwardly from said sleeve members, said cap stone being provided with an annular recess, and a plurality of triangular recesses to receive said reinforcing ring and said paddle members.

3. In a grinding mill of the disc type, a cap stone, a stationary mill stone, a rotatable mill stone fixedly mounted in the cap stone, each of said mill stones having axially disposed, generally cylindrical cavities in the opposed faces thereof, a pumping member adapted to be mounted within and removed as a unit from the cavity of the runner stone, the pumping member comprising a generally circular plate having paddle holders secured thereto at equally circumferentially spaced distances and extending outwardly from the face thereof, pumping paddles detachably secured within said paddle sockets, and means for bolting the pumping member to the cap stone within the cavity of the rotatable stone, triangular recesses being positioned within the cap stone to receive said paddle sockets.

References Cited in the file of this patent UNITED STATES PATENTS 109,046 Pepler Nov. 8, 1870 603,064 Mole Apr. 26, 1898 727,156 Lacey May 5, 1903 765,281 Hermann July 19, 1904 1,153,918 Hollstein Sept. 21, 1915 1,488,235 Dotzer Mar. 25, 1924 2,330,067 Macek, Sr., et al Sept. 21, 1943 FOREIGN PATENTS 20,045 Germany Nov. 7, 1882 21,998 Norway Feb. 5, 1912 35,838 Austria Ian. 11, 1909 

